This invention relates to an exterior view mirror for a motor vehicle of the type which is adapted to be mounted on the side of the vehicle and to be foldable to a position closely adjacent to the side of the vehicle to facilitate passage of the vehicle through narrow passageways and parking of the vehicle in confined spaces. Patent Specification SU-A-1137264 discloses a clutch having a component formed from shape memory alloy and arranged so that when the component is heated by an electrical heater, the driving and driven elements of the clutch disengage from one another. It is also known from
Patent Specification EP-A-0173433 that the electrical resisitivity of shape memory alloys of nickel and titanium is such that an element formed therefrom can conveniently be transformed from its relaxed phase to its force-exerting phase by passing an electric current through it.